Electronic tube



July 5, 1938. Y K. SCHLESINGER ELEQTRONIC TUBE Filed July 24, 1954 igl phragm) is reproduced as, preferably, electrostatic or static-magnetic means.

Patented July 5, 1938 PATENT OFFICE ELECTRONIC TUBE Kurt Schlesinger, Berlin, Germany,

Radioaktiengesellschaft D. S. Loewe,

Steglitz, Germany Application. July 4 Claims.

The object of the invention is an electron discharge tube in which the steepness and also the form, of the characteristic may be selected as desired, and which enables operations to be performed without reversal of the phase and oscillations to be generated by geometric back-coupling.

According to the invention a comparatively long electron radiator, forexample -20 mm. in length, having the smallest possible cross-section (-i. e. either a cathode or an intermediate diain the plane of an anode by a suitable electron-optical system and defiected by suitable means (for example deflecting plates).

By giving the anode a suitable shape and also by suitable adjustment of the initial position of the ray in relation to said anode there may be obtained any desired effect (for example rectificationor amplification) and also any desired form of characteristic.

It is desirable according to the invention to construct the anode and the deflecting means according to the particular purpose for which the tube is to be employed, and on each occasion to use the tube only for the one purpose.

According to the invention, the anode may consist of two parts, the one preferably having the shape of the reverse image of the other, and

arranged with the least possible intermediate spacing from the other-as to be insulated from each other by the vacuum-of which parts the oneis employed as working anode, whilst the other acts as auxiliary anode. It is also convenient in accordance with the invention to furnishythewall of the bulb as completely as possible with. a metallic coating, and if necessary to employ this metallic coating as additional auxiliary anode.

By suitable connection of the Working and auxiliary anode it is possible without difficulty to maintain the complete load of the anode circuit permanently constant.

The electron-optical reproduction maybe obtained both by the use of electro-magnetic aswell if necessary mixed It is an essential feature as regards the arrangement according to the invention that the reproduction requires to take place only in the one direction, viz., in the smaller dimensions of the electron radiator.

' If the reproduction occurs by the use of an electrostatic electron-optical system, it has been found desirable to employ an intermediate diaphragmas the object to be reproduced, and to said lugs should be considerably assignor to Berlin'- 24,1934, Serial No. 736,703 In Germany I uly 26, 1933 7 concentrate preliminarily the electrons proceeding from the cathode onto this diaphragm.

The entire tube, in accordance with the invention, is screened oil against external electrostatic and magnetic eilects, and more particularly also against the earth field, as completely as possible, preferably by the use of completely or substantially closed containers composed of iron, sheet iron or the like.

A form: of embodiment of the invention is illustrated by Way of example in the appended drawing, wherein Fig.1 shows in schematic sectional elevation a valve according to the invention,

the arrangement of ;10

Fig. la. is a plan view of the working and ,15

auxiliary anodes of the valve asseen for instance from the cathode side, I i

Fig. 2 shows the electron-optical system of the valve shown in Fig. 1, while Figs. 3 and 4 show two connection arrangements for electron valves according to the invention, and l Fig. 5 shows a further possible arrangement of the two anodes.

In Fig, 1: I5 is the glass bulb which is furnished with a metallic coating l3 at least on the side facing the anode, 6 the cathode, -l a halfcylinder surrounding the cathode, 8 the diaphragm to be reproduced, iii the electron-optical system, comprising the slotted discs-I and 4 and also the element 2 arranged between said discs, 9 and I0 are the deflecting plates, II and I2 the working anode and auxiliary anode, whilst l4 represents the metallic screening container.

As shown in the drawing, the half-cylinder l potential of, say, 200 volts.

The electrons proceeding from the long filament cathode are preliminarily concentrated onto the longand preferably very thin slot of the diaphragm and the slot is then reproduced sharply with the least possible enlargement in the plane of the anode by the system I6.

The electron-optical system is shown again separately in Fig. 2, in which I is the rear and 4 the front diaphragm; The middle element consists of the diaphragm 2 and the lugs 3 and 5 disposed at some distance from the diaphragm aperture. The distance between greater (for example twice as great) than the width of the aperture, and the width of the lugs should be at least as great (preferably just as great) as the distance between the same. Practically the width of the aperture may amount, for example, up to l or 2 mm. The rear diaphragm I being arranged so close to the plate 2, that practically no breaking field may arise between the same, the length of the entire electron-optical system may amount to not more than 12-15 mm.

The cathode filament 6 should be arranged at a certain distance from the front plane of the half-cylinder 1. This distance may amount for example to 25 mm.

It is assumed that the anode H is employed as working anode.

If now the ray or the anode is so adjusted or arranged that the ray in the position of rest meets against the point I! (see Fig. 1a), the tube acts as rectifier. If on the other hand the electron bundle is so adjusted that the same in the stationary position meets against any point of the inclined edge of the anode, for example the point l8, the tube acts as amplifier.

By giving the sloped edge a suitable form, the tube may be provided with any desired characteristic.

Thus, for example, the bounding edge may be furnished with the shape of an exponential curve or any other curve form.

The sensitiveness and the extent of movement of the electron bundle in the tube may be adjusted as desired by suitable arrangement and forming of the deflecting plates.

For example, for the use as a first potential amplifier stage the plates may be constructed as relatively tilted plates of, for instance, 20 mm. in length, which plates at the end facing the electron-optical system may possess a spacing of 1 mm., and at the opposite end a spacing of 2 mm. from each other.

Since the steepness of the characteristic depends on the sharpness of line of the electronoptical reproduction, it is desirable in accordance with the invention tron radiator with the ment.

A reproduction of the diaphragm on the scale of 1:1 or on a similar scale is, however, diificult to obtain in practice with regard to the fact, that the tube should be made comparatively short.

According to the invention, the arrangement may be such, that the tube does not appreciably exceed approximately 15 cm. in length, and the enlargement is not more than, for example, 5:1. In spite of this a very sharp line may be obtained with the use of very thin diaphragm slots having a width in the order of 0.1 mm. or even less.

As shown by Fig. 3, the two anodes II and I2 may be connected with the same potential source over the preferably equal-sized resistances l9 and 20.

If the anodes are situated very close together and the bounding curves thereof represent reversed images of each other, it is possible to obtain at the condensers 2|, equal but phase-reversed potentials. It will be quite obvious from this that the tube according to the invention enables the phase to be selected, on the single condition that both anodes are passed out.

In Fig. 4 there is illustrated by way of example an oscillation connection making use of the tube according to the invention.

The oscillatory circuit 23 is linked up with the anode II, which in turn is connected with least possible enlargeto reproduce the elec- 22 two completely the one deflecting plate It). As quite readily apparent, the oscillations in this arrangement are produced by geometric back-coupling.

The adjustment of the working point in a given tube according to the invention may take place by means of suitable biases at the deflecting plates.

It is also possible to allow the electrons to enter obliquely the space between the deflecting plates, and to furnish the one deflecting plate with a negative bias of such extent that the ray in the stationary position leaves the deflecting plate system in the direction of the axis of the tube. This arrangement permits of completely wattless control.

An increase in the sensitiveness may be obtained according to the invention by applying to the one deflecting plate the control potential and to the other deflecting plate a potential of equal extent but with reverse phase.

By the use of a connection of this kind the otherwise practically unavoidable distortions in the shape of the image are safely avoided.

To avoid anode reactions it is possible in accordance with the invention to provide between the deflecting system and the anodes a diaphragm raised to a constant positive potential (for example anode potential).

As shown in Fig. 5, it is alsopossible to arrange the auxiliary anode and the working anode in two different planes one behind the other. In this case the bounding line of the plate facing the ray must be inclined with respect to the plane of the non-deflected bundle of electrons.

Naturally the arrangement according to the invention may be modified in its details without departing from the basic idea of the invention. The invention is in no way limited to the forms of embodiment quoted solely by way of example.

As cathode there may conveniently be employed a metallic vapour cathode. The substance to be atomized for producing the cathode and also for producing the high vacuum, for example barium, may be provided on the element 1, or if desired on a special cap. The metallic coating on the wall may if desired alsobe produced by atomizing a metal.

In practice it is possible only with extreme difliculty to obtain a reproduction of the electron radiator which is even over its entire length.

While the middle part of the reproduction is entirely without fault, irregularities occur sometimes at the ends. It is accordingly desirable in respect of the forms of embodiment of the invention described in the above to make the length of the reproduction greater than the Width of the working anode, so that the irregularities sometimes occurring at the ends are unable to take eifect.

In order to avoid irregularities of this nature the slots in the diaphragm plates may in accordance with the invention means of oval closure members.

It is also possible, in addition to the one pair of deflecting plates, to perform an additional magnetic deflection or an additional electrostatic defiection in a direction vertical to the first deflection.

By means of high-frequency control in the one deflecting direction and, say, tone-frequency control in the other direction it is possible to obtain modulation completely free of harmonics and distortion.

The tubes according to the invention are, '15

be closed 01f by therefore, extremely important for superheterodyne receivers, but also for transmitters. Appreciable importance is also possessed by the tube according to the invention for television apparatus.

Surprisingly it has been found that the arrangement according to the invention may be operated without difficulty with comparatively low anode voltages in the order of 200 volts. Thus, the new valves may be used in all arrangements: of the known types.

I claim:

1. An electron-discharge device comprising means including an elongated electron source for producing a substantially unidirectional stream of electrons having an elongated cross-section, an electron-optical system for producing a sharp electron image of said source, comprising electrodes adapted to produce, if supplied with relatively different potentials, fields having substantially no component in a direction parallel to the main direction of said elongated source, so that the cross-section of said stream is substantially influenced by these fields only in a direction which forms right angles with the axis of said stream and with the main direction of said source, and means for laterally deflecting said electron stream.

2. An electron-discharge device comprising means including an elongated electron source for producing a substantially unidirectional stream of electrons having an elongated cross-section, an electron-optical system for producing a sharp electron-image of said source, comprising electrodes adapted to produce, if supplied with relatively different potentials, fields having substantially no component in a direction parallel to the main direction of said elongated source, so that the cross-section of said stream is substantially influenced by these fields only in a direction which forms right angles with the axis of said stream a and with the main direction of said source, means for laterally deflecting said electron stream, and an anode having an edge situated to be hit by said stream in at least one of the positions said stream, is apt to assume, said edge being disposed at an acute angle with respect to the main direction of the elongated cross-section of said stream.

3. An electron-discharge device comprising means including an elongated electron source for producing a substantially unidirectional stream of electrons having an elongated cross-section, an electron-optical system comprising electrodes adapted to produce, if supplied with relatively different potentials, fields having substantially no component in a direction parallel to the main direction of said elongated source, so that the cross-section of said stream is substantially influenced by these fields only in a direction which forms right angles with the axis of said stream and with the main direction of said source, means for laterally deflectingsaid electron stream, and a plate-shaped anode disposed at right angles to the axis of said electron stream and having an edge situated to be hit by said stream in at least one of the positions said stream is apt to assume, said edge being disposed at an acute angle with respect to the main direction of the elongated cross-section of said stream, said electron-optical system being adapted to project onto the plane of said anode a sharp electron image of said source.

4. An electron-discharge device comprising means including an elongated electron source and a diaphragm having a slot-shaped aperture parallel to said source for producing a substantially unidirectional stream of electrons having an elongated cross-section, an electron-optical system comprising electrodes adapted to produce, if supplied with relatively different potentials, fields having substantially no component in a direction parallel to the main direction of said elongated source, so that the cross-section of said stream is substantially influenced by these fields only in a direction which forms right angles with the axis of said stream and with the main direction of said source, means for laterally deflecting said electron stream and a plate-shaped anode disposed at right angles to the axis of said electron stream and having an edge situated to be hit by said stream in at least one of the positions said stream is apt to assume, said edge being disposed at an acute angle with respect to the main direction of the elongated cross-section of said stream, said electron-optical system being adapted to project onto the plane of said anode a sharp image of said aperture.

KURT SCI-ILESINGER. 

